Carbon Monoxide Releasing Curves from Measurements during Indoor Charcoal Burning: - Systematic Research on Toxic Levels for Humans

Objective: The Federal Institute for Risk Assessment (BfR) Doc-Center has received more and more reports of cases of carbon monoxide (CO) poisoning, some even with fatal outcomes after indoor use of charcoal grills. CO is odorless, colorless, non-irritant and does not produce any other warning effect perceptible to humans. The BfR and the Federal Institute for Materials Research and Testing (BAM) have completed a cooperative research project to investigate the toxic concentrations of CO that are reached when charcoal grills or open fires are used indoors. Methods: The first test series were conducted in a 1 m3 measuring chamber. Since the situation of larger interiors could not be reproduced, additional measurements had to be taken (with 800 g of glowing charcoal each) in a larger cloud chamber with a spatial volume of 19 m3. This chamber provides a good model for a small garage or a living room. CO concentrations were measured both under the ceiling and in the immediate vicinity of the grill. Systematic experiments were conducted. The data collected provided the basis for additional computer simulations, where the distribution of CO in rooms of any size could be calculated. Results: The glowing charcoal releases considerable amounts of toxic gases, notably CO. Based on calculations in a closed garage where 800 g of charcoal are burned for 30 min, CO concentrations of between 750 and 1100 ppm (parts per million) are to be expected. Based on clinical data, 200 ppm of CO in the ambient air causes slight headaches after 2 h. At 800 ppm, dizziness and nausea are experienced. After about 2 h of exposure to such a concentration, humans lose consciousness. Within no more than 2 h of glowing embers from 800 g of charcoal, CO concentrations exceeding 3000 ppm were measured, which are fatal for humans after a few minutes. Conclusion: According to the release curves, dangerous carbon monoxide levels are already reached within a relatively short time. Even when windows, doors and the garage door are opened for “safety reasons”, fatal CO concentrations can build up rapidly. It is strongly recommend that no burning materials such as charcoal are used indoors as a heat source for grilling, cooking or heating.